Ken’s Tractor

Copyright Ken, VK7KRJ.
Last revised: September 01, 2001.

 

After several years of pushing a wheel barrow around our 1 1/4 acre block, I decided a small lawn tractor would be a much better idea. At about the same time, and for the same reasons I also decided a ride-on lawn mower would be good- however we could not afford to buy either so I decided to build them.

This beast is the outcome of those thoughts. It has taken a couple of years of part-time work (with a lot of thinking time) using hand tools plus a welder and oxy-acetylene cutting gear. I did cheat a little and have a friend of mine do two machining jobs on his small lathe, but other than that it was the time-honoured firm of Messrs. Hackit & Weld (successors to Bodgeit & Bolt) that did the rest.

The chassis is 3 inch angle iron, about 1/4 inch thick, suitably cut, bent and welded; the back end started life as a Subaru independent suspension back axle. I dismantled the C.V. joints and welded a piece of pipe into the cups that held the joints, shortening the overall length of the axle to just on 4 feet with the wheels attached. The assembly is firmly bolted to the chassis, the only suspension movement is the "give" of the tyres.

Much thought and discussion went into the choice of an automatic gearbox- in the end it was the lack of having to build a clutch release mechanism that clinched it- after some 6 months of use it has turned out to be a very good decision.

 

           

click for larger images

 

Engine and automatic gearbox is from a Datsun 120Y

Bore/Stroke .......................73 x 70

Compression ratio .............9:1

Torque .............................70ft/lbs @ 3600rpm

Power ..............................68bhp @ 6000rpm

Using Subaru diff. (approx 3.7:1) and an extra 3:1 reduction :-

                                           Speeds in gears (Km/H)
               Overall ratio          @500rpm    @6000rpm

1st                41.7:1                    1.3             15.2

2nd                   24.1:1                    2.2             26.3

3rd                15.5:1                    3.4             40.7

 

Just in case anyone thinks this project was done in a nice, comfortable, warm workshop- here is my "workshop", 

under the shelter of some blackwood trees with one of our 4-legged lawn mowers and the donor car in the background

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